The Present Invention relates to apparatus for tensioning tracks of track-type vehicles, for example armored combat vehicles, in which the deflection or idler wheel of the track rotatably mounted on a bearing pin is pivotal in such a manner that the length of the track run is increased or decreased.
In prior art track tensioning apparatus, known for example from DT-OS 16 30 118 and 19 52 939, French Pat. No. 1,514,404 and U.S. Pat. Nos. 2,561,901 and 3,332,725, the bearing pin carrying the deflection wheel is rigidly mounted to a rocker which in turn is mounted in the chassis by means of a bearing journal not in alignment with the bearing pin. The track tension is obtained by the rocker being held in a corresponding pivot position under the force of a spring or a hydraulically produced force.
The Prior art apparatus which maintains this pivot position, possibly with a certain spring resilience, are of a complicated construction and bulky. In the case of combat vehicles they are also exposed to enemy fire and can thus be the cause of trouble in that the loss of track tension makes driving or at least adjustment of the track tension impossible.
The present invention is directed to an apparatus which overcomes such disadvantages and which further reduces the construction expenditure and space requirements for track tensioning means. According to one aspect of the present invention there is provided apparatus for tensioning tracks of track-type vehicles for example armored combat vehicles, in which the deflection or idler wheel of the track rotatably mounted on a bearing pin is pivotal in such a manner that the length of the track run is increased or decreased, wherein the bearing pin is pivotal with respect to its support element about an axis of rotation disposed parallel adjacent the axis of rotation of the deflection wheel but still within the bearing pin and wherein means are provided for locking the bearing pin with respect to its support element in given angular positions.
By mounting the bearing pin eccentrically with respect to its support and making the extent of the eccentricity adjustable, the means for tensioning the track can be arranged at a location protected from enemy fire between the deflection wheel and the chassis; thus, no means are required laterally of the deflection wheel.
In the preferred form of the invention the support element is a support journal which is mounted within the bearing pin and projects into the latter substantially up to the level of the deflection wheel.
The track is tensioned by pivoting or rotating the bearing pin around the support journal whereby the path of the track is increased or decreased.
The bearing pin may have large dimensions to obtain the desired eccentricity and to take up considerable forces.
According to another aspect of the invention there is provided apparatus for tensioning tracks of track-type vehicles, for example armored combat vehicles, in which the deflection wheel of the track rotatably mounted on a bearing pin is pivotal in such a manner that the length of the track run increases or decreases, and the deflection wheel is mounted on a rocker pivotably mounted in a rocker bearing on the chassis of the track-type vehicle in such a manner that the connecting line between the rocker bearing and the axis of rotation of the deflection wheel coincides substantially with the resultant of the directions of the two chain runs converging towards the deflection wheel, the rocker bearing lying between the axis of rotation of the deflection wheel and the portion of the track bearing on the deflection wheel. Preferably at the end of the rocker opposite the rocker bearing a support journal is secured. Further the bearing pin preferably comprises a bore extending eccentrically to the axis of rotation of the deflection wheel and parallel thereto for receiving the support journal and means are provided for securing and locking the bearing pin with respect to the support journal in predetermined angular positions of the bearing pin.
The fixing of the angular position of the bearing pin with respect to the support element may be made in infinitely variable manner or in steps, with large track forces the stepwise fixing is to be preferred because it operates in form-locking manner and not in a non-positive manner like the previously mentioned fixing.
The arrangement of the support journal on a rocker permits a certain pivoting of the deflection or idler wheel and thus avoids a rigid mounting thereof which is disadvantageous when there is a danger of the deflection wheels coming against the ground in uneven terrain.
The adjustment of the bearing pin with respect to its support element, i.e. the adjustment of the eccentricity and thus the track tension, is preferably effected by means of a tensioning key which engages a plurality of lateral faces, or one or more recesses at the second end face of the bearing pin in a positive manner. The free end of the tensioning key may be brought in to engagement with the track so that it is possible to perform this adjustment by slowly driving the vehicle forwards or backwards, i.e. without any additional auxiliary means and in particular without any human effort.
Further, details and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.